Keloids are dermal tumors which arise in response to trauma. This disorder occurs with high frequency in Black populations. Available evidence indicates that some individuals have a hereditary predisposition to keloid formation. It is also suggested that this tumor growth involves over proliferation and abnormal collagen production by dermal fibroblasts. In an attempt to identify the primary gene defect involved and its mode of action we will: (1) examine the collagen produced by keloid tissue and cultured fibroblasts isolated therefrom, (2) examine growth characteristics of cultured keloid and normal fibroblasts in order to define an in vitro phenotype attributable to the keloid gene, (3) determine the effect of this phenotype on macromolecular synthesis, (4) determine whether structural alterations of the cell or the extracellular matrix are correlated with changes in cell proliferation, (5) examine possible differences in the regulation of collagen production by normal and keloid fibroblasts in vitro by comparing their amino acid pools, tRNA's, subunit synthesis, intracellular processing, transport, and extracellular processing under normal growth conditions and under conditions found to alter cell proliferation. As yet unknown environmental factors can alter the expression of the "keloid gene." Study of factors which affect the in vitro phenotype of keloid fibroblasts may suggest methods of manipulating the patient's environment to prevent the growth of this tumor.